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Research On Open Shape-Based Directional Relationship Query Technology

Posted on:2007-12-12Degree:MasterType:Thesis
Country:ChinaCandidate:J ShiFull Text:PDF
GTID:2178360212495504Subject:Computer application technology
Abstract/Summary:PDF Full Text Request
Being critical in geographic information systems, image interpretation, etc, direction relationships in spatial database are used as selection conditions. The efficiency of the query also attracts more concern of academia in recent years.A processing method based on absolute reference frame was explored in this paper. Based on current directional relationship model, we extended an open shape model and defined the topological operations on it, which converts the directional relationship query to topological operations between open shapes and closed geometry objects.Range quey strategy was used to implement static directional queries, while we used open shape to process the qualitative and quantitative queries. This paper introduced the specific modeling and processing method of quantitative queries based on open shape, and proposed a universal arithmetic in different refference frame with quantitative query technology. And then proved the advantage of open shape strategy in CPU cost and I/O cost compared with traditional range query strategy by experiment.The time-parameterized directional relationship query technology was proposed in this paper, which contraposed the moving objects' dynamic attribution directly. In stead of finitely static directional relationship queries, it calculated the object and the query window's intersection period and used it to renew the results. Finally, we compared the intersection period arithmetic's relative performance of traditional strategy and open shape strategy with experiment, and proved the open shape strategy's advantage in performance.
Keywords/Search Tags:OpenShape, Directional Relationship Query, Qualitative Query, Quantitative Query, Time-Parameterized Query
PDF Full Text Request
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